Metrohm 761 Compact IC - Manual (Page 190)

5 Notes – Maintenance – Faults
761 Compact IC
180
5.2.7 Regeneration of the suppressor module
Regenerating a suppressor operating
at reduced capacity
If the suppressor units are exposed to certain heavy metals (e.g. iron) or
organic contaminants for long periods of time, these can no longer be
completely removed by the regeneration solution normally used (20
mmol/L H
2
SO
4
). This diminishes the capacity of the suppressor units,
which, in milder cases, results in a reduced sensitivity to phosphates
and, in severe cases, in a strong increase in the baseline. If such ca-
pacity problems occur at one or several positions, the suppressor units
must be treated as follows:
1 Disconnect suppressor from IC system
• Disconnect suppressor from separating column and detector.
2 Regenerate suppressor
• Rinse each suppressor unit for about 15 min with one of the
following solutions:
Contamination with heavy metals
1 mol/L H
2
SO
4
Contamination with organic cationic complexing agents
0.1 mol/L H
2
SO
4
/ 0.1 mol/L oxalic acid / acetone 5%
Severe contamination with organic substances
0.2 mol/L H
2
SO
4
/ acetone ≥ 20%
The 6.1826.060 pump tubing is made of PP and must not
be used for rinsing with solutions which contain organic
solvents. In such cases, rinse with different pump tubing
or a different pump.
3 Connect suppressor to IC system
• Reconnect suppressor to the IC system. If capacity problems
persist, replace the suppressor rotor (see section 5.2.9).
Regenerating the suppressor in case
of high counterpressure
If excessive counterpressure is observed in one or several suppressor
units, treat the units as follows:
1 Disconnect suppressor from IC system
• Disconnect suppressor from separating column and detector.
2 Regenerate suppressor
• Connect the inlet capillary 99 marked "H
2
SO
4
" to the inlet
capillary 26 using coupling 33 (see Fig. 10 and Fig. 16). This
connects the suppressor module directly to the high-pressure
pump.